This is exactly for what it says it's for....hard water! I cannot fathom paying $95 for an expensive water filter in my shower head for the hard water. The hard water makes my brown hair a little brassy and dull, so I make sure to use this once a week, sometimes every other week (if I forget!) and it does the job well.
Make sure you don't have any cuts or wounds on your hand because this WILL...read more burn.
Here's how I use it: pour a tiny amount of powder crystals in your hand, add water, and mix to make a "paste" and apply to scalp--massage very gently. repeat this until the entire packet is gone and leave on for 5 minutes in the shower.
It's a little time consuming, so expect to take a long shower when you use this!
Malibu's other hair packet treatments are great too, and reasonably priced.